“Detached HEAD” sounds scary, but it’s a normal Git state that’s easy to understand and recover from.

What is HEAD?

HEAD is a pointer to the current commit you’re working on.

• When you create a repository, HEAD points to the first commit.
• After each new commit, HEAD moves to point to that commit.
• When you switch branches, HEAD points to the latest commit on that branch.

Normally, HEAD points to a branch, which points to a commit. That’s HEAD being “attached.”

What is Detached HEAD?

Detached HEAD happens when HEAD points directly to a commit instead of a branch.

This occurs when you check out a specific commit:

git checkout 5a06d3ca5e7adb6e67

Now HEAD points directly at that commit, not at any branch.

Why Would You Enter Detached HEAD?

Common scenarios:

1. Debugging: You’re trying to find which commit introduced a bug, so you check out specific commits to test them.
2. Exploring history: You want to see how the code looked at a specific point in time.
3. Using git bisect: The bisect process checks out commits automatically, putting you in detached HEAD state.

Getting Back to Normal

When you’re done exploring, simply check out a branch:

git checkout main

HEAD is now attached to main again.

The Dangerous Scenario

The problem arises when you make commits while in detached HEAD state.

git checkout abc123      # Now in detached HEAD
# make some changes
git add .
git commit -m "Important fix"
# You now have a commit that no branch points to!

If you check out a different branch now, those commits could be lost (eventually garbage collected) because no branch references them.

Saving Work from Detached HEAD

If you’ve made commits in detached HEAD state, create a branch before switching:

# Create a branch at the current commit
git branch my-rescue-branch

# Switch to it
git checkout my-rescue-branch

Or do both in one command:

git checkout -b my-rescue-branch

Now your commits are safe on a proper branch.

Summary

State	HEAD Points To
Attached	A branch (which points to a commit)
Detached	Directly to a commit

Key takeaways:

• Detached HEAD is normal when exploring history.
• Check out a branch when you’re done looking around.
• If you make commits in detached HEAD, create a branch before leaving.
• git checkout -b new-branch is your friend for saving work.

Lessons in this unit:

0:	Introduction
1:	Working with Remotes
2:	Squashing Commits
3:	Rebase vs Merge
4:	Git Bisect for Debugging
5:	Git Worktrees
6:	Git Submodules
7:	▶︎ Understanding Detached HEAD
8:	Managing Secrets in Git
9:	Git Workflows and Best Practices
10:	How to push to 2 repositories at the same time and keep them in sync
11:	How to update a Git branch from another branch
12:	Git, detached HEAD
13:	Trigger deploys on Netlify with submodules
14:	A Git Cheat Sheet
15:	Git, squashing vs not squashing
16:	An incomplete list of great Git tutorials
17:	Git, what if you forgot to add a file to a commit?
18:	Git workflow to manage work on multiple branches
19:	How to set up the Git SSH keys